A composition which contains an alkali-soluble resin, such as novolak resin, and a quinonediazide compound as photosensitive material is generally used as a photosensitive composition for lithographic printing plate or a positive photoresist composition for fine processing. Hitherto, a great number of photosensitive compositions of the type which contain an alkali-soluble resin and a quinonediazide compound have been developed. Some instances of them are described in A. Reiser, Photoreactive Polymers, John Wiley & Sons (1989).
As those photosensitive compositions can withstand some levels of practical use, they have so far been used as photosensitive compositions for lithographic printing plates and resists for fine processing. In the present situation, however, it is required of a photosensitive composition for lithographic printing plate to have higher sensitivity and exhibit better development latitude than ever.
Also, a resist for fine processing is now in the circumstances that higher resolution and image reproduction better in pattern shape than ever are required thereof.
In order to heighten resolution and reproduce images with a good pattern shape, it has so far been thought that the use of a resist having high contrast (.gamma. value) is advantageous. Therefore, resist-composition arts which can answer the aforementioned purpose have been developed. Such arts are disclosed in a great number of publications. As for the novolak resin in particular, which constitutes the main part of positive photoresist, a great deal of patents have been applied for its monomer composition, molecular weight distribution, synthetic method and so on, and have brought passable results. As for the photosensitive material also, which is the other main component, there have been disclosed the compounds with various structures which have been regarded as effective for increasing the contrast.
The 1,2-naphthoquinonediazide compounds of polyhydroxy compounds having certain specific structures have been proposed in large numbers for the purpose of heightening the resolution. For instance, such compounds are disclosed in JP-A-57-63526 (the term "JP-A" as used herein means an "unexamined published Japanese patent application), JP-A-60-163043, JP-A-62-10645, JP-A-62-10646, JP-A-62-150245, JP-A-63-220139, JP-A-64-76047, JP-A-1-189644, JP-A-2-285351, JP-A-2-296248, JP-A-2-296249, JP-A-3-48249, JP-A-3-48250, JP-A-3-158856, JP-A-3-228057, JP-A-4-502519, U.S. Pat. Nos. 4,957,846, 4,992,356, 5,151,340, and 5,178,986, European Patent 530,148, and so on. Although those photosensitive materials were successful in heightening the resolution, they left the sensitivity insufficient.